The present invention relates to a gas insulated disconnecting switch, which is particularly suitable for use in a gas insulated switching apparatus.
One of the problems associated with a disconnecting switch filled with such insulating gas as SF.sub.6 is the breakage of the tips of the stationary and movable contacts or electrodes due to impact created at the time of closing the disconnecting switch.
Another problem has arisen as a disconnecting switch is used, for instance, for switchover in a transmission system shown in FIG. 1. For effecting switchover from one transmission line A to another B, a disconnecting switch BD is closed and a disconnecting switch AD is then opened. The disconnecting switch AD has to interrupt its share of the load current, with the recovery voltage being determined by the voltage drop across the disconnecting switch BD and the associated transmission line. Such current may be near the magnitude of the rated current, if difference in resistance between the lines A and B is great.
If an arc proof piece of copper-tungsten alloy is mounted on the end of each contact to improve resistance against impact, powder of decomposition product formed of the vaporized alloy and the decomposed constituent of the SF.sub.6 gas is deposited on an insulating spacer, with the result that insulating strength is lowered.